UK PAYE tool

Payslip Health Score

Q: What is a 'good' score?

80+ generally appears healthy. Below 60 is worth a structured review.

Q: Does the score replace HMRC?

No - it is a heuristic flag, not an official assessment.

Q: Why does the tax code matter so much?

It is the single biggest driver of how much PAYE you pay. Wrong code = wrong tax.

Q: Why penalise non-cumulative codes?

They smooth less well over the year and are often a sign HMRC needs more info.

Q: Will the score change month to month?

Yes, especially if HMRC changes your code or your pension % changes.

A 0-100 score across five dimensions of your payslip. Spot soft spots in 30 seconds.

What a result looks like

Sample: 1257L code, 5% pension matched, NI A, 0 unknown items, cumulative. Score 100 - appears consistent.

When to use this tool

Quarterly self-checks.
After a job change.
After HMRC sends a coding notice.
Before applying for a mortgage or loan.

What the result bands mean

80-100

Appears healthy.

60-79

Some items worth reviewing.

< 60

Possible issue - review with payroll / HMRC.

Common mistakes

Counting employer pension as your %.
Reading W1 as part of the tax code number.
Treating reasonable but unusual NI categories as wrong.

Worked example

Code BR, 3% pension vs 5% match, NI A, 1 unknown deduction, cumulative.

Tax 8 + Pension 10 + NI 20 + Deductions 14 + PAYE 20 = 72.

Band: medium - tax code and pension worth reviewing.

Frequently asked questions

What is a 'good' score?

80+ generally appears healthy. Below 60 is worth a structured review.

Does the score replace HMRC?

No - it is a heuristic flag, not an official assessment.

Why does the tax code matter so much?

It is the single biggest driver of how much PAYE you pay. Wrong code = wrong tax.

Why penalise non-cumulative codes?

They smooth less well over the year and are often a sign HMRC needs more info.

Will the score change month to month?

Yes, especially if HMRC changes your code or your pension % changes.

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Last verified: 2026-05-03.

Disclaimer: Heuristic score, not an official assessment.